This you can do yourself. These seatcovers are installed with a combination of plastic clips around the outer edge & velcro on the inside. If the seat is powered, make sure the seat is at it's farthest forward position. (the track will be sticking out the back of the seat cushion.) You can use a couple of pieces of wire from a 12 volt battery to the power wires of the seat to move it forward on the tracks. This is done so that the seat will stand on it's own on the bench. Otherwise the seat will keep falling over backwards, fighting you every inch of the way throughout the whole job. If you can take 'em apart, you can put 'em back together. Remove tthe little handle for the tilt mechanism. You don't have to be gentle taking the cover off as your gonna be throwing it away. The foam in the seat is probably screwed up under the rip on the outside edge. Typical. Glue the foam back together wherever it needs it, using trim adhesive. Comes in a black tube, made by 3M. Put the glue on both pieces, stick 'em together, then pull them apart & let the glue dry. 10-15 minutes or so. When you stick the pieces together after the glue has dried, you have one shot at getting it right, so make sure that you have it lined up. Glue a piece of scrap fabric under the foam, side to side, front to back. Use some spray adhesive on both pieces, letting the glue dry till tacky before you slap it together for good. This will help the foam stay together & keep the frame of the seat from working into the foam again.
To install the new cover, turn it inside out, center it on the foam, push dowm the velcro, attach the rear of the cover underneath to the frame, then roll the cover over the foam & frame, starting at the front corners first. Don't be afraid to beat it into submission. Once the cover is on, & you're happy with the way it looks, tap the pin for the tilt handle sticking into the cover with a small ballpeen hammer. This will give you a nice clean hole for that pin to come through, with out cutting a hit & miss hole with scissors.
You can probably do this job without seperating the backrest from the cushion. If you're not too confident that you can get it back together, take pix of it as you take it apart, just to remember what goes where & how.
Fairly simple to do. Ask me any more Q's that you have if you get stuck. Good luck.